CD34+ hematopoietic stem cells, Rubius used bioengineering technology on CD34+ hematopoietic stem cells from healthy O-type donors for cell therapy products, such as RTX-134 for PKU (phenylketonuria), RTX-240 for AML, and RTX-321 (RTX-aAPC) for HPV 16+ cancer. This evidence concerns the gene CD34 and phenylketonuria.